The present disclosure relates to an apparatus and method for administering medicament for inhalation by a patient and, more particularly, to a dry powdered medicament inhaler.
Metered dose medicament inhalers are well known for dispensing medicament to the lungs of a patient, for treating asthma for example. Existing types of medicament dispensing inhalers include pressurized propellant inhalers, aqueous solution inhalers, and dry-powdered inhalers.
U.S. Pat. No. 5,503,144 to Bacon, for example, shows a dry powdered inhaler. The inhaler includes a reservoir for containing a dry powdered medicament, a metering chamber for removal of the powdered medicament from the reservoir in discrete amounts, and an air inlet for entraining the removed powdered medicament through a mouthpiece upon patient inhalation.
Another example is U.S. Pat. No. 5,971,951 to Ruskewicz, which shows an inhaler including a motor driven cam mechanism for extruding aqueous medicament through a porous membrane to form a medicament aerosol for inhalation by a patient. The inhaler also includes sensors, circuitry and a microprocessor that determines the rate of patient inhalation and operates the extrusion mechanism only upon adequate inhalation levels.
A pressurized propellant, or xe2x80x9caerosolxe2x80x9d inhaler is shown in U.S. Pat. No. 5,447,150 to Bacon, which also discloses a simple, mechanical actuation assembly for ensuring that medicament is dispensed from the inhaler only upon adequate inhalation by a patient. The actuation assembly works by applying a pre-load to a valve of the aerosol container sufficient to cause a dose release, but prevents the release by applying a pneumatic resisting force. The dose of medicament is then released upon a patient inhalation strong enough to move a door within the assembly, which in turn releases the pneumatic resisting force.
What is still desired, however, is a new and improved inhaler for administering medicament for patient inhalation. Preferably, the new and improved inhaler can be used with dry powdered medicament. In addition, the new and improved inhaler will preferably include mechanical assemblies for metering doses of medicament, managing medicament reservoir pressure, and counting the number of doses remaining in the inhaler.
The present disclosure, therefore, provides a new and improved medicament inhaler having a unique dose metering system. The inhaler includes a mouthpiece for patient inhalation, a delivery passageway for directing an inhalation induced air flow through the mouthpiece, a channel extending from the delivery passageway, and a reservoir for containing medicament, with the reservoir having a dispenser port connected to the channel. In a preferred form, the dose metering system includes a cup received in the channel, which is movable between the dispenser port and the delivery passageway, a cup spring biasing the cup towards one of the dispenser port and the passageway, and a yoke movable between at least two positions. The yoke includes a ratchet engaging the cup and preventing movement of the cup when the yoke is in one of the positions, and allowing movement of the cup when the yoke is in another of the positions.
The present disclosure also provides a medicament inhaler having a unique reservoir pressure system. The inhaler includes a sealed reservoir having a dispenser port, and a channel communicating with the dispenser port, and a cup assembly movably received in the channel. In a preferred form, the pressure system includes a pressure relief port in the channel, and a conduit providing fluid communication between an interior of the sealed reservoir and the pressure relief port of the channel. The cup assembly includes a recess adapted to receive medicament when aligned with the dispenser port, a first sealing surface adapted to seal the dispenser port when the recess is unaligned with the dispenser port, and a second sealing surface adapted to seal the pressure relief port when the recess is aligned with the dispenser port and unseal the pressure relief port when the recess is unaligned with the dispenser port.
The present disclosure additionally provides a medicament inhaler having a unique dose counter. The inhaler includes a mouthpiece for patient inhalation, a dose metering system including a pawl movable along a predetermined path during the metering of a dose of medicament to the mouthpiece by the dose metering system, and a dose counter. In a preferred form, the dose counter includes a bobbin, a rotatable spool, and a rolled ribbon received on the bobbin, rotatable about an axis of the bobbin. The ribbon has indicia thereon successively extending between a first end of the ribbon secured to the spool and a second end of the ribbon positioned on the bobbin. The dose counter also includes teeth extending radially outwardly from the spool into the predetermined path of the pawl so that the spool is rotated by the pawl and the ribbon advanced onto the spool during the metering of a dose to the mouthpiece.
Thus, the present disclosure provides a new and improved inhaler including a simple, accurate and consistent mechanical dose metering system that dispenses dry powdered medicament in discrete amounts or doses for patient inhalation, a reservoir pressure system that ensures consistently dispensed doses, and a dose counter indicating the number of doses remaining in the inhaler.
Further features and advantages of the presently disclosed inhaler will become more readily apparent to those having ordinary skill in the art to which the present disclosure relates from the drawings and the detailed description.